A method has been described for the synthesis of tritiated 16-Beta-OH-DHEA. The radioactive steroid has been administered to normotensive and low-renin hypertensive patients and an assay procedure developed to measure the excretion rate of this steroid in the urine of these patients before and after the administration of aminoglutethimide. Studies have also been carried out on tritiated 18-OH-DOC after intravenous dosing of normotensive and low-renin hypertensive patients. Attempts have been made to isolate and synthesize the proposed major urinary metabolite of 18-OH-DOC, namely 18-OH-TH-DOC using both in vitro and chemical techniques.